In the normal operation of a can body manufacturing operation using apparatus such as the type illustrated in U.S. Pat. No. 3,425.251 to Maytag, it is necessary to change the forming sleeve on the front end of the ram at periodic intervals because of wear and tear on the forming sleeve. At each change, the forming sleeve is reground and polished so that the diameter of the forming sleeve is reduced at each change. This of course results in the formation of can bodies having cylindrical sidewalls with smaller inner diameters after each change of the forming sleeve. In one type of operation, it is customary to change the forming sleeve between fifty and sixty times, so that can bodies of fifty to sixty differing diameters are produced. This also has an effect on the apparatus wherein a portion of the can body having uneven edges at the open end thereof is trimmed away. In such apparatus, it is conventional to use a collapsible mandrel wherein a plurality of resilient fingers are integral with a support having a longitudinal axis wherein the resilient fingers extend in axial and radially outward directions from the support. A locking ring is used in conjunction with the support and the resilient fingers to limit the radially outward movement of the resilient fingers while permitting limited radially inward movement of the resilient fingers The resilient fingers are designed to contact the inner peripheral surface of the can body so as to hold the can body for rotation therewith. The nature of the resilient fingers is such that when the diameter of the inner peripheral surface has been changed by several changes of the forming sleeve, it is necessary to change the locking ring because either too much force has to be placed on the can bodies to move the can bodies over the resilient fingers having an outer diameter for can bodies having larger inner diameters or the resilient fingers will not hold the can body firm enough to prevent relative rotation between the can body and the resilient fingers. Thus, as described below, even though the difference in inner diameters of the can bodies and outer diameters of the resilient fingers as controlled by the locking rings is very small, it is necessary to change the locking rings for can bodies of smaller or larger inner diameters for the satisfactory operation of the can body trimming apparatus. In trimming apparatus used with the can body manufacturing apparatus described above, it is customary to have six different locking rings to accommodate the fifty to sixty differing sizes of can bodies. The forming sleeves for the above operation have a maximum diameter of 2.4783 inches and a minimum diameter of 2,4723 inches and the six locking rings have internal cylindrical surfaces for limiting the radially outward movement of the resilient fingers having diameters of 2.007; 2.009; 2.011; 2.013; 2.015 and 2.017 inches. Therefore, after a plurality of changes of the forming sleeves, it is necessary to change the locking ring of the trimming apparatus. In some trimming apparatuses, a plurality of trimming stations are mounted on a rotating turret so that, when can bodies having a different internal diameter are to be processed, it is necessary to change a plurality of locking rings.